Using the Reference Build for till rebuilds

On first startup IPC connects to the Worldpay Payments Hub (WPH) to pull down files containing information unique to its identity. A subset of these files contain an encryption key that is unique to that instance of the TID and is used to prevent the same TID from being configured and active on more than one till.

The encryption key is refreshed once a year by default, or more frequently, when IPC connects to the WPH. This is called the key change process.

If there’s a mismatch between the encryption key that IPC holds in its local files, and the key that WPH believes is current for that TID, IPC will fail to initialise.

The necessity for keeping the encryption key in sync between WPH and IPC has implications when replacing an existing instance of IPC from the reference build. This will be required if a till has suffered a hard disk corruption or catastrophic failure resulting in having to replace the IPC instance.

Once the till is rebuilt with the reference build, and IPC has been configured with MID and TID details, it is necessary to synchronise the TID’s encryption key between WPH and IPC.

The is achieved by flagging a key change for the TID at WPH. When IPC starts up and connects to WPH the value of the WPH flag forces a refresh for the encryption key for that TID. This results in WPH and IPC both holding the same encryption key and IPC will then be enabled to accept transactions.

When rebuilding a till the process will be:

  1. First, contact the Worldpay support team and request the key change flag to be set for the TID.

    If there are a significant number of tills to be rebuilt e.g. 10 or more, then please advise your Worldpay contact well in advance so that special arrangements can be put into place as required.

  2. Rebuild the till from the reference build

  3. Configure IPC with MID and TID details

  4. Start the IPC application

IPC will then connect to WPH, pull down configuration details for the TID and perform the encryption key refresh process.